Roukoz Chamoun

Surgical approaches for resection of vestibular schwannomas: translabyrinthine, retrosigmoid, and middle fossa approaches

Surgical removal remains one of the key treatment modalities for vestibular schwannomas. A team approach between a neurotologist and a neurosurgeon offers the patient the expertise of both specialties and maximizes the chances for an optimal outcome. Vestibular schwannomas can typically be resected through 1 of 3 main surgical approaches: the translabyrinthine, the retrosigmoid, or the middle fossa approaches. In this report and videos, the authors describe and illustrate the indications and surgical techniques for the removal of these tumors.

Hearing preservation after middle fossa vestibular schwannoma removal: are the results durable?

Objective To describe 5-year hearing preservation rates following microsurgical excision of vestibular schwannoma (VS) via the middle cranial fossa (MCF) approach. Study Design Case series with chart review. Setting This study was performed at a tertiary care academic medical center. Subjects and Methods Fifty-seven subjects with VS underwent resection via an MCF approach between February 1998 and January 2009. Pure-tone average (PTA) and word recognition score (WRS) were obtained preoperatively, immediately postoperatively, and at 5-year follow-up. Results Preoperative serviceable hearing (American Academy of Otolaryngology—Head and Neck Surgery class A/B) was present in 49 (86%) of the 57 patients, with an average PTA of 23 dB (range, 1-50 dB) and an average WRS of 97% (range, 76%-100%). Immediate postoperative serviceable hearing was maintained in 27 (55%) patients, with an average PTA and WRS of 31 dB (5-50 dB) and 96% (70%-100%), respectively. Five-year follow-up was available for 16 of the 27 patients. Twelve (75%) of the 16 patients maintained serviceable hearing with an average PTA and WRS of 35 dB (4-49 dB) and 95% (84%-100%), respectively. Of the 16 subjects who did maintain class A or B hearing, the mean change in PTA and WRS was 5 dB and 0.4%, respectively. Of the 4 patients who did not maintain class A/B hearing, average change in PTA and WRS was 16 dB (4.5-23 dB) and 16% (0%-40%), respectively. Conclusions For patients with VS in whom serviceable hearing is preserved following the MCF approach, the long-term hearing outcome remains durable in most patients.

Predicting Consistency of Meningioma by Magnetic Resonance Imaging.

Objective Meningioma consistency is important because it affects the difficulty of surgery. To predict preoperative consistency, several methods have been proposed; however, they lack objectivity and reproducibility. We propose a new method for prediction based on tumor to cerebellar peduncle T2-weighted imaging intensity (TCTI) ratios. Design The magnetic resonance (MR) images of 20 consecutive patients were evaluated preoperatively. An intraoperative consistency scale was applied to these lesions prospectively by the operating surgeon based on Cavitron Ultrasonic Surgical Aspirator (Valleylab, Boulder, Colorado, United States) intensity. Tumors were classified as A, very soft; B, soft/intermediate; or C, fibrous. Using T2-weighted MR sequence, the TCTI ratio was calculated. Tumor consistency grades and TCTI ratios were then correlated. Results Of the 20 tumors evaluated prospectively, 7 were classified as very soft, 9 as soft/intermediate, and 4 as fibrous. TCTI ratios for fibrous tumors were all ≤ 1; very soft tumors were ≥ 1.8, except for one outlier of 1.66; and soft/intermediate tumors were > 1 to < 1.8. Conclusion We propose a method using quantifiable region-of-interest TCTIs as a uniform and reproducible way to predict tumor consistency. The intraoperative consistency was graded in an objective and clinically significant way and could lead to more efficient tumor resection.

Prediction of Consistency of Pituitary Adenomas by Magnetic Resonance Imaging

Objective Pituitary adenomas are typically soft. The prevalence of fibrous adenomas is ∼ 5 to 13%. Firm tumors are difficult to remove by curettage or suction. Predicting fibrous adenomas by magnetic resonance (MR) imaging is typically difficult and unreliable. We propose a new prediction method based on MR T2-sequence intensity. Methods The MRIs of 36 consecutive patients with nonsecreting macroadenomas were evaluated preoperatively by a blinded radiologist. Using an MR T2-weighted sequence, regions of interest were sampled from the adenoma and cerebellar peduncle, and the ratio was calculated. Intraoperatively, tumors were graded prospectively for their consistency by the operating surgeon. Results There were 28 soft and 6 fibrous tumors. Unpaired t test for these ratios was found to be statistically significant (p < 0.0240; 95% confidence interval, -0.8229 to -0.06207). Mean values for soft tumors were found to be 1.918 (standard error of the mean [SEM] = 0.08212); firm tumors, 1.475 (SEM = 0.1179). Soft tumors were associated with ratios > 1.5 (sensitivity 100%; specificity 66.7%); firm tumors were associated with ratios < 1.8 (sensitivity 100%; specificity 42.9%). Conclusion Fibrous adenomas are typically diagnosed intraoperatively. However, their resection can be technically challenging. Using T2 intensity ratios on routine preoperative MRI allows identification of these challenging cases. The surgeon can then be better prepared for the surgical resection.

Neuroendoscopic treatment of symptomatic giant Virchow-Robin spaces.

Background: Virchow–Robin spaces (VRS) or perivascular spaces are interstitial cystic spaces surrounding the vasculature of brain parenchyma and course from the subarachnoid space. Small VRS (<2 mm) appear in all age groups, but can enlarge and be confused with other lesions like cystic neoplasms. These enlarged VRS are termed giant tumefactive perivascular spaces (GRPVS). Case Description: We present the case of a 50-year-old male who presents with right eye pain, blurred vision, headache, and gait imbalance. He was diagnosed with GRPVS and underwent an endoscopic third ventriculostomy and cyst fenestration. Postoperative imaging showed a decrease in size of the ventricular system with evidence of flow through the aqueduct and ventriculostomy. Brainstem VRS cysts decreased in size. Conclusion: Unlike the other small number of case reports, this patient is unique in his age of presentation and successful endoscopic method of treatment. The endoscopic approach provided great exposure and adequate access to the lesions. Clinically, symptoms improved, cyst size decreased, and need for permanent shunt placement was averted.

Three-Dimensional Printed Model Used to Teach Skull Base Anatomy Through a Transsphenoidal Approach for Neurosurgery Residents

BACKGROUND: Skull base anatomy through a transsphenoidal approach is challenging for the neurosurgical resident to conquer. OBJECTIVE: To demonstrate that stereolithography, or 3-dimensional (3-D) printing, is a useful educational tool for neurosurgery residents to learn skull base anatomy. METHODS: Before any formal teaching, residents were brought into the operating room where they were asked to identify key structures seen through an endoscopic transsphenoidal approach. Scoring was based on correctly naming the anatomical structures. After the initial testing, all residents participated in a didactic lecture reviewing this anatomy by using 2-dimensional pictures. Residents were then divided into 2 groups: A and B. Group B residents were additionally taught through neurosurgical simulation using a 3-D printed model and an endoscope. Following all formal teaching, residents were retested in the operating room. RESULTS: A maximum score of 8 points was possible if all structures were identified correctly. Group A had mean scores of 2.75 on initial testing compared with 5 after the lecture (P = .041 using 2-tailed t test). Group B had mean scores of 2.75 on initial testing compared with 7.5 after the lecture and 3-D model simulation (P = .002). When comparing mean scores after formal teaching in groups A and B, 5 vs 7.5 were obtained for lecture only vs lecture and 3-D model simulation, respectively (P = .031). CONCLUSION: Three-dimensional models used in neurosurgical simulation to teach skull base anatomy through a transsphenoidal approach showed objective and subjective improvement in testing scores in neurosurgery residents. This study confirms that 3-D models are a useful educational tool.

Nervus intermedius meningioma

OBJECTIVE To report a case of meningioma arising from the nervus intermedius. METHODS This paper comprises a case report, literature review, and discussion regarding the presentation of a nervus intermedius meningioma, comparing and contrasting this to other relevant neoplasms of the internal auditory canal and cerebellopontine angle. RESULTS Tumours of the cerebellopontine angle include vestibular schwannomas, facial schwannomas and, more rarely, nervus intermedius schwannomas. The nervus intermedius is a division of the facial nerve at the cerebellopontine angle, with parasympathetic and afferent somatic components. Our patient presented with progressive hearing loss. An ipsilateral internal auditory canal mass at the fundus, as indicated by magnetic resonance imaging and electroneuronography, was suggestive of vestibular schwannoma. Intra-operative dissection revealed a nervus intermedius tumour. Histological evaluation indicated a meningioma rather than a schwannoma. CONCLUSION This is the first reported case of meningioma involving the nervus intermedius. The implications this pathology may have on surgical approach, facial nerve outcomes, and the need for improved pre-operative imaging and intra-operative monitoring are discussed. A review of the current literature on nervus intermedius tumour is provided.

Very Large Metastases to the Brain: Retrospective Study on Outcomes of Surgical Management

BACKGROUND The incidence of brain metastases is rising. To our knowledge, no published study focuses exclusively on brain metastases larger than 4 cm. We present our surgical outcomes for patients with brain metastases larger than 4 cm. METHODS This is a retrospective chart review of inpatient data at our institution from January 2006 to September 2015. Primary end points included overall survival, progression-free survival, and local recurrence rate. RESULTS Sixty-one patients had a total of 67 brain metastases larger than 4 cm: 52 were supratentorial and 15 were infratentorial. Forty-three patients underwent surgical resection. Average duration of disease freedom after resection was 4.79 months (range, 0-30 months). Excluding patients with residual on immediate postoperative magnetic resonance imaging, the average rate of local recurrence was 7 months (range, 1-14 months). Overall survival after surgery excluding patients who chose palliation in the immediate postoperative period averaged 8.76 months (range, 1-37 months). Thirty-five of 43 patients (81.4%) had stable or improved neurologic examinations postoperatively. Six patients (13.95%) developed surgical complications. There were 3 major complications (6.98%): 2 pseudomeningoceles required intervention and 1 postoperative hematoma required external ventricular drain placement. There were 3 minor complications (6.98%): 1 self-limited pseudomeningocele, 1 subgaleal fluid collection, and 1 postoperative seizure. CONCLUSIONS Surgery resulted in stable or improved neurologic examination in 81.4% of cases. On statistical analysis, significantly increased overall survival was noted in patients undergoing surgical resection, and those with higher Karnofsky Performance Scale and lower number of brain metastases at presentation. There is a need for further studies to evaluate management of brain metastases larger than 4 cm.

Safety, Efficacy, and Cost-Analysis of Percutaneous Endoscopic Gastrostomy and Ventriculoperitoneal Shunt Placement in a Simultaneous Surgery

BACKGROUND Limited historical data suggest that concomitant placement of both a ventriculoperitoneal (VP) shunt and percutaneous endoscopic gastrostomy (PEG) tube is associated with an increased risk of complications, including VP shunt infections. Here we compare the outcomes and cost difference between 2 groups of patients, one in which a VP shunt and PEG tube were placed in the same operation and the other in which separate operations were performed. METHODS A total of 10 patients underwent simultaneous placement of a VP shunt and PEG tube. This group was compared with a group of 18 patients that underwent separate placements. Hospital billing charges were used to compare the total cost of the procedures in the 2 groups. RESULTS Eight of the 10 patients presented with aneurysmal subarachnoid hemorrhage. The average length of stay was 25 ± 2 days for the simultaneous procedure group and 43 ± 7 days for the separate procedures group. The average duration of follow-up was 12 ± 3 months after simultaneous placement. No patient in the simultaneous surgery group had signs of infection or shunt malfunction at last follow-up. The overall complication rate was significantly lower in the simultaneous surgery group. A cost analysis demonstrated significant cost savings by completing both procedures in the same surgical procedure. CONCLUSIONS Simultaneous placement of a PEG tube and VP shunt is safe, efficacious, and cost-effective. Thus, in patients requiring both a VP shunt and PEG tube, placement of both devices in a single surgical procedure should be considered.

Socioeconomic Factors Affecting Discharge Status of Patients with Uncomplicated Transsphenoidal Adenohypophysectomy

Objectives The number of transsphenoidal adenohypophysectomies (TSAs) surgeries has grown significantly since 1993. While there has been an overall decreasing trend in length of stay (LOS), socioeconomic factors may impact hospitalization. This study explores the impact of socioeconomic factors on LOS and total charges in uncomplicated patients undergoing TSA. Design Retrospective cohort. Setting 2009 to 2013 Nationwide Inpatient Sample. Participants Patients undergoing TSA without medical complications. Main Outcomes Measures LOS and total charges. Results A total of 6,457 patients were identified, of which 17.2% had secreting tumors. Patients with secreting tumors stayed 2.95 days versus those with nonsecreting tumors stayed 3.26 days (p < 0.001). Discharge to other than self‐care was the largest contributing variable for both subsets, increasing both LOS and total charges. Patient factors that drove longer LOS and increased total charges for both subsets included metropolitan domicile, having a lower median income, Hispanic ethnicity, and having an increased amount of Agency for Healthcare Research and Quality (AHRQ) comorbidity indices. Having private insurance predicted a shorter LOS and lower total charges. Conclusions These results demonstrate that, even without complications, patients can be delayed in their discharge. While several socioeconomic factors significantly predict LOS and charges, the discharge disposition ultimately has the greatest effect. This suggests that efforts should focus on improving organizational factors such as coordination with social work and outside facilities to decrease LOS and charges for this patient population.